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.Dd March 7, 2016
.Dt EXEC_SYS_REGISTER 2
.Os
.Sh NAME
.Nm exec_sys_register ,
.Nm exec_sys_unregister
.Nd register/unregister for resident execution
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/resident.h
.Ft int
.Fn exec_sys_register "void *entry"
.Ft int
.Fn exec_sys_unregister "int id"
.Sh DESCRIPTION
The
.Fn exec_sys_register
system call registers the binary of the calling process for resident
execution.
This snapshots the vmspace and causes future
.Fn exec Ns s
of the specified binary to use the snapshot directly rather than load
and relocate a new copy.
.Pp
The
.Fn exec_sys_unregister
system call unregisters a resident binary identified by
.Ar id ,
or the binary of the calling process if
.Ar id
is -1 ,
or all registered binaries if
.Ar id
is -2.
.Pp
Both can only be done by the superuser.
.Sh RETURN VALUES
.Rv -std exec_sys_register exec_sys_unregister
.Sh ERRORS
The
.Fn exec_sys_register
system call will fail if one of the following occurs:
.Bl -tag -width Er
.It Bq Er EEXIST
The binary is already resident.
.It Bq Er ENOENT
No associated vnode exists.
.It Bq Er EPERM
The caller does not have sufficient permissions.
.El
.Pp
The
.Fn exec_sys_unregister
system call will fail if one of the following occurs:
.Bl -tag -width Er
.It Bq Er ENOENT
The specified
.Fa id
could not be found.
.It Bq Er EPERM
The caller does not have sufficient permissions.
.El
.Sh SEE ALSO
.Xr resident 8
.Sh HISTORY
The
.Nm
and
.Nm exec_sys_unregister
system calls first appeared in
.Dx 1.0 .
.Sh AUTHORS
.An -nosplit
The
.Nm
and
.Nm exec_sys_unregister
system calls were written by
.An Matthew Dillon
and this manual page was written by
.An Sascha Wildner .